1. Technical Field
The present disclosure is related to a semiconductor light source driving apparatus which drives semiconductor light source elements, such as light emitting diodes and laser diodes, and a projection type display using the semiconductor light source driving apparatus.
2. Related Art
JP 2009-302295 A discloses a semiconductor light source driving apparatus capable of continuously driving series-connected light emitting diodes which have no disconnection failure to emit a light and informing a user of disconnection failure, even after the disconnection failure occurs in one or more of series-connected light emitting diodes.
This semiconductor light source driving apparatus is provided with a plurality of series-connected light emitting diodes, a power supply circuit which supplies electric power to the light emitting diodes, and a detection unit which detects disconnection when the disconnection occurs in either one of light emitting diodes. The semiconductor light source driving apparatus is further provided with resistors connected in parallel with the respective light emitting diodes, switch elements connected to the respective resistors in series, and an indicator which indicates the disconnection.
The semiconductor light source driving apparatus is further provided with a controller which controls a switch element so that when the disconnection occurs in one of light emitting diodes, a current flows through the resistor connected in parallel with the light emitting diode having the disconnection. This arrangement enables lighting operation of the light emitting diodes other than the light emitting diode in which disconnection occurs. The controller controls the indicator to inform a user of the disconnection.
By such a configuration, even after disconnection failure occurs in one or more of series-connected light emitting diodes, the light emitting diodes having no disconnection failure can continuously be driven to emit light and the disconnection failure can be informed a user.